This invention relates to shock-absorbing cushions. Commonly used shock-absorbing cushions are formed of air-cell cloth, foam plastic or rubber, etc., but they have the following defects in practical use.
1. The air-cell cloth is made of two sheets sealed together to pinch a plurality of independent air cells not communicating with one another, and each air cell is at atmospheric pressure which is unadjustable, having a constant shock-absorbing force so that it cannot be changed to cope with different objects.
2. The air cells contained in air-cell cloth are separately sealed to have the same inner pressure as the exterior atmospheric pressure, having no inherent supporting force for pressure or shock. Therefore, if the air cell(s) should be broken and become flat with the air having escaped, it (they) would have no supporting force for pressure or shock, and the cloth would become useless.
3. Every air cell in air-cell cloth is independent, and sealed to have a constant pre-set pressure, unable to be changed by inflation to have a wide adaptability.
4. Air-cell cloth has a flat shape, unable to be formed as a cubic shape having three dimensions.
5. The inner pressure of the air cells in air-cell cloth can not exceed 1 atm (kg/cm2) or 14.7 psi, restricted by its manufacturing method of "vacuum absorbing formation" so that air-cell cloth is impossible to make if the thickness or the hardness of the material surpasses a certain value, with the result that the supporting force of the air-cell cloth cannot be changed by the thickness, the hardness of the material, the shape or the size of the air cells.
6. Each air cell in air-cell cloth receives a different shock force when struck by an exterior object and the cloth is unable to disperse evenly the shock force received mainly because the cells do not communicate with one another.
7. A solid shock-absorbing cushion of foam plastic has a certain shock-absorbing force restricted by the property of the material so that it can hardly be used for different occasions, objects or things.
8. As the shape of a solid shock-absorbing cushion is impossible to change once made by a mold, it can hardly meet the necessity to protect the object it is used for by conforming completely to the shape and the size of the object.
9. U.S. Pat. No. 4,054,960 titled "Inflatable Body Support Cushion Particularly to Support a Woman During Pregnancy" is a king of air-cushion bed for a pregnant woman made of a moldable material, but does not have the function of flexibility or inherent supporting force, as can be seen on page 1, lines 50-51 in the patent specification.
10. U.S. Pat. No. 4,629,433 titled "Inflatable Articles and Method of Making Same" acquired by Magid, has a preventing function of deforming and extension of an inflatable article once inflated with air, but it is made of pieces so that the articles have no inherent supporting force, as can be seen on page 1, lines 64-65 page 6, lines 67-68 in the patent specification.
11. U.S. Pat. No. 1,382,831 titled "Pneumatic Cushion" is a sealed bag made of two sheets of material and said two sheets have thickened inner sides such that the bag can hold the outer surface flat after it is inflated with air. But it can hardly be flexible and lacks vertical supporting force against pressure.
12. U.S. Pat. No. 2,465,265 titled "Pneumatic Bed" acquired by Rogers is a bag made of two sheets sealed at the circumferential edge and a third sheet is additionally put between and connected with the two sheets so that it can hold an extremely flat surface, but it has no flexibility or inherent supporting force against pressure or shock, as can be seen on pages 1-2, lines 49-52.
13. U.S. Pat. No. 2,372,218 titled "Pneumatic Mattress" is provided with valves to inflate or deflate the mattress, but said pneumatic mattress has no inherent supporting force against pressure and the inflating valves have a different structure and function from the flexible pump to be disclosed herein.
14. U.S. Pat. No. 4,115,885 titled "Water Cushion and Method of Using the Same" acquired by Davis is a shock-absorbing bag filled with water, having no vertical supporting force against pressure.
15. U.S. Pat. No. 4,217,705 titled "Self-Contained Fluid Pressure Foot Support Device" is a bag sealed around the periphery of two sheets of non-elastic fabric and having a special section provided with round hollow cells defined by hot sealing, said round hollow cells being inserted by foot supporting cushions for supporting a foot. The cushion body is originally flat and has no inherent supporting force against pressure, as can be seen on page 7, lines 7-10. The so called supporting force is caused by the foot supporting cushions.
16. U.S. Pat. No. 2,677,906 titled "Cushioned Inner Sole for Shoes and Method of Making the Same" acquired by Reed is a shoe sole made of two sheets having the periphery heat sealed and another sheet connected with the upper and the lower sheets so as to make up an inner shoe sole having a specially flat surface. But the air cushion has little flexibility and air cells independent to one another, whereby it is impossible to disperse the pressure received evenly around the structure and the inflating operation is complicated as well.
17. U.S. Pat. No. 3,991,420 titled "Protective Baseball Batting Garment" acquired by Savarino is a protective jacket for baseball batting but the padded sections are not provided with air cushions.
18. U.S. Pat. No. 4,614,000 titled "Patient Undersheet for Preventing Bed Sores" acquired by Mager is a bed undersheet for a patient having a sheet of air-cell cloth with a sheet of fabric mounted thereon. The air-cell cloth has no structure or supporting force, nor does its air-cells communicate with one another, so it cannot be developed to make up a three-dimensional structure.
19. French Patent No. 540,623 is an air cushion made of two sheets of material sealed such that a plurality of independent air cells are formed therein, without any linking passages among the air cells. The air cushion has little flexibility and each air cell does not have even pressure.
20. Belgian Patent No. 645,151 is a shock-absorbing cushion made of two sheets of material with a water absorbing layer sandwiched between the two sheets, and the two sheets are provided with round recesses. It is made of two flat sheets, devoid of potential supporting force against pressure or shock, nor can it be inflated.
21. German Patent No. 807,010 titled "Soft Layer Baby Diaper" is provided with an inflated air cushion attached to an inflating pump. The cushion body is made of two sheets, devoid of inherent supporting force against pressure of flexibility caused by the absence of communicating passages.
22. French Patent No. 1,118,087 is made of two sheets sealed together with heat, and an extra two sheets are connected with said two sheets by means of round recesses, on which through holes are provided for air flow, so it lacks potential supporting force against shock or pressure.
23. U.S. Pat. No. 2,028,060 titled "Protector" 10 acquired by Gilbert is an inflatable sport protecting cushion made of a plurality of square hollow tubes combined together and communicating with each other by means of connecting tubes. As it is provided with two sheets having square grooves, the square tubes may be deformed after being inflated so that the surface may not be flat enough.
24. U.S. Pat. No. 4,670,995 titled "Method for Manufacturing Soles with an Air Cushion" acquired by the same applicant as the present application is a shoe sole having a structure of two sheets provided with round recesses. Although it has an even pressure pervasion owing to the communication air-cells, flexibility and an inherent supporting force against pressure, it has a drawback that the smoothness of the surface is not so good after being inflated because of the pending supporting force of the air cells.
The U.S., French, German and Belgian patents discussed above have common drawbacks that they have little or no inherent supporting force against pressure or shock, little flexibility, and can have an unsmooth surface after being filled with air. Besides, they cannot be combined to make up an air cushion with a cubic structure to conform to a curved surface of the human body and to an inherent shock-absorbing force, excellent flexibility and evenly pervasive pressure.
In view of the defects in conventional shock-absorbing cushions, this applicant has acquired U.S. Pat. Nos. 4,670,995 and 7,422,131, Japanese Patent No. 1,709,140, Korean Patent No. 35,963 and Australian Patent No. 564,808 for an invention relating to an air cushion for a shoe sole. Now this applicant has further devised the present invention to furnish a shock-absorbing cushion that has the possibility of adjusting the inner pressure, flexibility in being adaptable to any hollow shape, the largest shock-absorbing dimension, and an inherent supporting force against pressure or shock. That is, this shock-absorbing cushion has in its hollow interior, a plurality of air cells communicating with one another, so that when inflated, air can flow here and there in the interior, and an inherent shock-absorbing elasticity even if it is broken. It can widely be applied to sports goods such as leg or shin guards, knee pads, shoulder pads, racket grips, football helmets, shoe soles, tools, seat cushions, and above have common drawbacks that they have little or no inherent supporting force against pressure or shock, little flexibility, and can have an unsmooth surface after being filled with air. Besides, they cannot be combined to make up an air cushion with a cubic structure to conform to a curved surface of the human body and to have an inherent shock-absorbing force, excellent flexibility and evenly pervasive pressure.
In view of the defects in conventional shock-absorbing cushions, this applicant has acquired U.S. Pat. Nos. 4,670,995 and 7,422,131, Japanese Patent No. 1,709,140, Korean Patent No. 35,963 and Australian Patent No. 564,808 for an invention relating to an air cushion for a shoe sole. Now this applicant has further devised the present invention to furnish a shock-absorbing cushion that has the possibility of adjusting the inner pressure, flexibility in being adaptable to any hollow shape, the largest shock-absorbing dimension, and an inherent supporting force against pressure or shock. That is, this shock-absorbing cushion has in its hollow interior, a plurality of air cells communicating with one another, so that when inflated, air can flow here and there in the interior, and an inherent shock-absorbing elasticity even if it is broken. It can widely be applied to sports goods such as leg or shin guards, knee pads, shoulder pads, racket grips, football helmets, shoe soles, tools, seat cushions, and packing material, utilizing the features just mentioned above.